München 2004 – wissenschaftliches Programm

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UP: Umweltphysik

UP 5: Satelliten und Anwendungen II

UP 5.6: Fachvortrag

Montag, 22. März 2004, 17:45–18:00, HS 221

Influence of Storms on Microwave Brightness Temperatures and Its Potential of Estimating Cloud Ice Using AMSU-B Water Vapor Channels — •Gang Hong, Georg Heygster, and Klaus Kunzi — University of Bremen, Institute of Environmental Physics , P.O. Box 330440, D-28334 Bremen

Downward looking brightness temperatures between 89 and 220 GHz were measured with the Millimeter-wave Imaging Radiometer (MIR) aboard the NASA ER-2 aircraft at 20 km altitude over four storms. Measurements were complemented by simultaneous observations with many other sensors. Analysis of these observations was conducted to investigate the influence of storms on microwave brightness temperatures. To investigate the effects of cloud ice and ice particle size distribution in storms on microwave brightness temperatures, radiative transfer simulations are also made using hydrometeor profiles obtained from three methods: (1) from a simple precipitating cloud model, (2) from the simultaneous aircraft radar observations, and (3) from the Goddard Cumulus Ensemble model. Results show that frequencies above 150 GHz are more sensitive to cloud ice, especially in the region of cloud anvil, and the brightness temperature differences at the three water vapor channels near 183.3 GHz greater than 0 K can be used as a criterion to discriminate the strong convection. All investigations of observations and simulations reveal the potential to estimate ice water path from microwave observations at AMSU-B water vapor channels near 183 GHz.